Cordray Frank E
Department of Orthodontics, Ohio State University, Columbus, Ohio, USA.
Am J Orthod Dentofacial Orthop. 2006 May;129(5):619-30. doi: 10.1016/j.ajodo.2004.10.015.
The seated condylar position (SCP), also known as centric relation (CR), is considered the most reliable and reproducible reference point for accurately recording the relationship of the mandible to the maxilla. Therefore, a determination of the SCP/CR is a prerequisite for the analyses of the dental interarch, condylar position, and skeletal relationships. The purpose of this prospective study was to statistically evaluate the 3-dimensional nature of dental interarch displacement and condylar displacement between the SCP/CR and maximum intercuspation or centric occlusion (MIC/CO).
The records of 596 consecutive asymptomatic patients having routine orthodontic treatment in a private practice were used. The initial premature occlusal contact and 3-dimensional dental interarch displacement were measured by the analysis of models, mounted on an articulator (Panadent, Grand Terrrace, Calif) in the SCP/CR, by using the modified (nonmanipulated) 2-piece wax SCP/CR recording method with deprogramming. Three-dimensional condylar displacement was measured by analysis of the graphic registrations, produced by condylar position instrumentation, and evaluated for frequency, direction, and magnitude of displacement.
The dental interarch discrepancy in the SCP/CR was significantly different from that observed in MIC/CO, with posterior premature contacts (94.0%), increased overjet, decreased overbite, midline differences, and Angle classification changes. A difference in condylar position between the SCP/CR and MIC/CO in at least 1 plane was detected for every asymptomatic patient and every condyle. The most prevalent types of directional change in condylar position were inferior (down) (97.0%) and distal (posterior) (66.7%) when the teeth were brought into MIC/CO. The mean difference in condylar position between the SCP/CR and MIC/CO was .86 mm in the horizontal plane, 1.80 mm in the vertical plane, and .26 mm in the transverse plane. No correlation was found between a patient's age or sex and the magnitude of condylar displacement.
There is a significant difference in the occlusion when it is dictated by the teeth and when it is dictated by the condyles. This difference is quantifiable at both the occlusal and condylar levels.
坐位髁突位置（SCP），也称为正中关系（CR），被认为是准确记录下颌骨与上颌骨关系的最可靠且可重复的参考点。因此，确定SCP/CR是分析牙弓间、髁突位置和骨骼关系的前提条件。这项前瞻性研究的目的是从统计学角度评估SCP/CR与最大牙尖交错位或正中咬合（MIC/CO）之间牙弓间位移和髁突位移的三维特征。
使用了一家私人诊所中596例连续接受常规正畸治疗的无症状患者的记录。通过在SCP/CR状态下安装在咬合架（Panadent，加利福尼亚州大露台市）上的模型分析，采用改良（未操作）的两片式蜡SCP/CR记录方法并解除程序控制，测量初始早接触和三维牙弓间位移。通过分析髁突位置测量仪生成的图形记录来测量三维髁突位移，并评估位移的频率(, )方向和大小。
SCP/CR中的牙弓间差异与MIC/CO中观察到的差异显著不同，存在后牙早接触（94.0%）(, )覆盖增加(, )覆合减小(, )中线差异和安氏分类改变。对于每例无症状患者和每个髁突，在至少一个平面上均检测到SCP/CR与MIC/CO之间的髁突位置差异。当牙齿达到MIC/CO时，髁突位置最常见的方向变化类型是向下（97.0%）和向后（远中）（66.7%）。SCP/CR与MIC/CO之间髁突位置的平均差异在水平面上为0.86毫米，在垂直面上为1.80毫米，在横断面上为0.26毫米。未发现患者年龄或性别与髁突位移大小之间存在相关性。
由牙齿决定的咬合与由髁突决定的咬合之间存在显著差异。这种差异在咬合和髁突水平均可量化。
